The receivers/decoders of audiovisual programmes offer more and more functionalities to the user. In addition to the essential functions aimed at receiving, recording and displaying programmes, the equipment has numerous interfaces for, for example, the communication with third devices, the configuration or even electronic money. The increasing development of digital products for domestic use, such as, for example, television, computers, organizers, mobile phones, data storage devices, printers, also increases the number of interfaces of programme receivers to make the interconnection to different home equipment possible.
While configurations including a large number of devices and interfaces make it possible for the user to benefit from comfortable functionalities, they induce however a high energy consumption through circuit multiplication. So, it becomes more and more important to control the energy consumption of devices for domestic use and also the energy consumption of an entire installation and more widely of an entire home.
There are now European directives in terms of energy consumption. These directives must be considered with care during the design steps of general public devices.
The energy consumption high reduction constraint, coupled with the necessity to be able to wake up the devices creates problems. It is necessary to have standby modes corresponding to the lowest possible energy consumptions and necessary to be able to wake up a device in standby mode, which requires that a sub-assembly of the device enabling waking-up remains operational in standby mode.
It is then usual, with the purpose of meeting these constraints, to use an architecture which comprises a power supply, a motherboard and a keyboard and display management board, sometimes called KDB, from the English acronym “Key and Display Board”.
In the following lines, the designations “motherboard”, “power supply” and “Key and Display Board” or even “KDB” do not however correspond necessarily to independent electronic boards but designate all the components which participate in the associated function.
So, “motherboard” designates all the electronic circuits fulfilling the functions supported by the equipment apart from those supported by the KDB and the supply of energy lines supported by the power supply.
The “KDB” designation designates all the circuits corresponding to the remote control receipt, keyboard management and display functions, as well as the control unit functions in standby mode. But these circuits can however be located on the same electronic board as all the circuits called here “motherboard”.
In the same way, the power circuits which enable the various supply lines to be provided in voltage and current from the electrical network to which the equipment is connected can be located on the same board as the circuits called here “motherboard”.
The designations used here only enable the person skilled in the art to better understand the overall architecture of the equipment within the scope of which the invention falls.
The KDB supports the elements necessary for data receipt for equipment control by a remote control. The remote control can however use any other type of communication such as Bluetooth as an example.
This architecture based on a motherboard and a KDB enables an economical management of the energy since, in standby mode, it is possible and easy to cut off the power supply of a very large number of functions present on the motherboard, or even the entire motherboard by maintaining the KDB supplied and operational for display and keyboard management and the receipt of the remote control frames. It is indeed usual, when a device receiving audiovisual programmes is configured in standby mode, to use the keyboard or the remote control to wake up the device and return to active mode.
In standby mode, it is also usual that the display remains operational to indicate to the user the operating mode (standby mode) as well as other information like the time for example. In this mode, the KDB is sometimes fully autonomous, the motherboard not being operational and not implementing a software application likely to update the contents of the display memory.
An important constraint during the design of a device designed on the basis of this architecture is to simplify as much as possible the KDB for implementation, cost and modularity reasons.
The KDB generally consists of a microcontroller, a clock circuit for time stamping; a display module sometimes comprising a display controller, a keyboard constituted by a set of keys connected to the microcontroller and a remote control frame receiver, also connected to the microcontroller.
The inputs-outputs ports of the KDB microcontroller are used for the interconnections with the different elements and in particular to constitute the keyboard, often by key matrixing in lines and columns and receive the signals from the receiver of the remote control.
The display controller manages the display autonomously. The modification of the information to be displayed is done by writing into the memory of the display controller from the motherboard and when the device is not in standby mode. The main control unit of the device receiving audiovisual programmes writes into the memory of the display controller via a communication interface such as for example a bus 120.
During the design of a general public device such as, for example, a receiver recorder of audiovisual programmes, it is not rare to reuse the basic architecture of an existing product and adapt it to the specific needs defined in specifications. The display can, for example, be of various types, such as electroluminescent with LED (“Light Emitting Diode” or VFD (“Vacuum Fluo Display”) or even of the LCD (Liquid Crystal Display) type and the information to be displayed for the user differ from one device to another.
According to the defined needs and the number of functions carried out by the device, the display must be able to display a more or less large number of information for the user like the number of the displayed programme, the time, messages constituted of alphanumeric characters, icons or pictograms symbolizing functions being used, maintenance or error information.
The adaptation of a display on an already existing KDB architecture is sometimes delicate since it can be necessary to integrate a display model while keeping the same display controller and the same microcontroller of the KDB.
The invention described enables, in the context defined above, the clever realisation of a display function when the memory of the display controller cannot be accessed in write mode, the equipment being in standby mode. The display must be modified according to the occurrence of an event.